The 45RFE/545RFE automatic transmissions is a sophisticated, multi-range, electronically controlled transmission
which combines optimized gear ratios for responsive performance, state of the art efficiency features and low NVH.
Other features include driver adaptive shifting and three planetary gear sets to provide wide ratio capability with
precise ratio steps for optimum driveability. The three planetary gear sets also make available a unique alternate
second gear ratio. The primary 2nd gear ratio fits between 1st and 3rd gears for normal through-gear accelerations.
The alternate second gear ratio (2prime) allows smoother 4-2 kickdowns at high speeds to provide 2nd gear pass-
ing performance over a wider highway cruising range.

The hydraulic portion of the transmission consists of the transmission fluid, fluid passages, hydraulic valves, and
various line pressure control components.

The primary mechanical components of the transmission consist of the following:

•

Three multiple disc input clutches

•

Three multiple disc holding clutches

•

Five hydraulic accumulators

•

Three planetary gear sets

•

Dual Stage Hydraulic oil pump

•

Valve body

•

Solenoid pack

The Transmission Control Module (TCM) is the “heart” or “brain” of the electronic control system and relies on infor-
mation from various direct and indirect inputs (sensors, switches, etc.) to determine driver demand and vehicle oper-
ating conditions. Depending on the vehicle configuration, the TCM may be a standalone module or it it may be
housed along with the Powertrain Control Module (PCM) in a single module. With this information, the TCM can
calculate and perform timely and quality shifts through various output or control devices (solenoid pack, transmission
control relay, etc.).

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AUTOMATIC TRANSMISSION - 45RFE/545RFE - SERVICE INFORMATION

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TRANSMISSION IDENTIFICATION

Transmission identification numbers are stamped (1)
on the left side of the case just above the oil pan seal-
ing surface. Refer to this information when ordering
replacement parts. A label is attached to the transmis-
sion case above the stamped numbers. The label
gives additional information which may also be neces-
sary for identification purposes.

GEAR RATIOS

The 45RFE gear ratios are:

1st . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.00:1
2nd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.67:1
2nd Prime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.50:1
3rd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.00:1
4th . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.75:1
Reverse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.00:1

GEAR RATIOS

The 545RFE gear ratios are:

1st . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.00:1
2nd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.67:1
2nd Prime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.50:1
3rd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.00:1
4th . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.75:1
5th . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.67:1
Reverse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.00:1

OPERATION

The 45RFE/545RFE offers full electronic control of all automatic up and downshifts, and features real-time adaptive
closed-loop shift and pressure control. Electronic shift and torque converter clutch controls help protect the trans-
mission from damage due to high temperatures, which can occur under severe operating conditions. By altering shift
schedules, line pressure, and converter clutch control, these controls reduce heat generation and increase trans-
mission cooling.

To help reduce efficiency-robbing parasitic losses, the transmissions includes a dual-stage transmission fluid pump
with electronic output pressure control. Under most driving conditions, pump output capacity greatly exceeds that
which is needed to keep the clutches applied. The 45RFE/545RFE pump-pressure control system monitors input
torque and adjusts the pump pressure accordingly. The primary stage of the pump works continuously; the second
stage is bypassed when demand is low. The control system also monitors input and output speed and, if incipient

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AUTOMATIC TRANSMISSION - 45RFE/545RFE - SERVICE INFORMATION

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